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npf.c revision 1.2 
      1 /*	$NetBSD: npf.c,v 1.2 2010/12/18 01:07:25 rmind Exp $	*/
      2 
      3 /*-
      4  * Copyright (c) 2009-2010 The NetBSD Foundation, Inc.
      5  * All rights reserved.
      6  *
      7  * This material is based upon work partially supported by The
      8  * NetBSD Foundation under a contract with Mindaugas Rasiukevicius.
      9  *
     10  * Redistribution and use in source and binary forms, with or without
     11  * modification, are permitted provided that the following conditions
     12  * are met:
     13  * 1. Redistributions of source code must retain the above copyright
     14  *    notice, this list of conditions and the following disclaimer.
     15  * 2. Redistributions in binary form must reproduce the above copyright
     16  *    notice, this list of conditions and the following disclaimer in the
     17  *    documentation and/or other materials provided with the distribution.
     18  *
     19  * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
     20  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
     21  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
     22  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
     23  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
     24  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
     25  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
     26  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
     27  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
     28  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
     29  * POSSIBILITY OF SUCH DAMAGE.
     30  */
     31 
     32 /*
     33  * NPF main: dynamic load/initialisation and unload routines.
     34  */
     35 
     36 #include <sys/cdefs.h>
     37 __KERNEL_RCSID(0, "$NetBSD: npf.c,v 1.2 2010/12/18 01:07:25 rmind Exp $");
     38 
     39 #include <sys/param.h>
     40 #include <sys/types.h>
     41 
     42 #include <sys/atomic.h>
     43 #include <sys/conf.h>
     44 #include <sys/kauth.h>
     45 #include <sys/kmem.h>
     46 #include <sys/lwp.h>
     47 #include <sys/module.h>
     48 #include <sys/percpu.h>
     49 #include <sys/rwlock.h>
     50 #include <sys/socketvar.h>
     51 #include <sys/uio.h>
     52 
     53 #include "npf_impl.h"
     54 
     55 /*
     56  * Module and device structures.
     57  */
     58 MODULE(MODULE_CLASS_MISC, npf, NULL);
     59 
     60 void		npfattach(int);
     61 
     62 static int	npf_dev_open(dev_t, int, int, lwp_t *);
     63 static int	npf_dev_close(dev_t, int, int, lwp_t *);
     64 static int	npf_dev_ioctl(dev_t, u_long, void *, int, lwp_t *);
     65 static int	npf_dev_poll(dev_t, int, lwp_t *);
     66 static int	npf_dev_read(dev_t, struct uio *, int);
     67 
     68 typedef struct {
     69 	npf_ruleset_t *		n_rules;
     70 	npf_tableset_t *	n_tables;
     71 	npf_ruleset_t *		n_nat_rules;
     72 } npf_core_t;
     73 
     74 static void	npf_core_destroy(npf_core_t *);
     75 static int	npfctl_stats(void *);
     76 
     77 static krwlock_t		npf_lock		__cacheline_aligned;
     78 static npf_core_t *		npf_core		__cacheline_aligned;
     79 static percpu_t *		npf_stats_percpu	__read_mostly;
     80 
     81 const struct cdevsw npf_cdevsw = {
     82 	npf_dev_open, npf_dev_close, npf_dev_read, nowrite, npf_dev_ioctl,
     83 	nostop, notty, npf_dev_poll, nommap, nokqfilter, D_OTHER | D_MPSAFE
     84 };
     85 
     86 static int
     87 npf_init(void)
     88 {
     89 #ifdef _MODULE
     90 	devmajor_t bmajor = NODEVMAJOR, cmajor = NODEVMAJOR;
     91 #endif
     92 	npf_ruleset_t *rset, *nset;
     93 	npf_tableset_t *tset;
     94 	int error = 0;
     95 
     96 	rw_init(&npf_lock);
     97 	npf_stats_percpu = percpu_alloc(NPF_STATS_SIZE);
     98 	npf_tableset_sysinit();
     99 	npf_session_sysinit();
    100 	npf_nat_sysinit();
    101 	npf_alg_sysinit();
    102 	npflogattach(1);
    103 
    104 	/* Load empty configuration. */
    105 	rset = npf_ruleset_create();
    106 	tset = npf_tableset_create();
    107 	nset = npf_ruleset_create();
    108 	npf_reload(rset, tset, nset);
    109 	KASSERT(npf_core != NULL);
    110 
    111 #ifdef _MODULE
    112 	/* Attach /dev/npf device. */
    113 	error = devsw_attach("npf", NULL, &bmajor, &npf_cdevsw, &cmajor);
    114 	if (error) {
    115 		/* It will call devsw_detach(), which is safe. */
    116 		(void)npf_fini();
    117 	}
    118 #endif
    119 	return error;
    120 }
    121 
    122 static int
    123 npf_fini(void)
    124 {
    125 
    126 	/*
    127 	 * At first, detach device, remove pfil hooks and unload existing
    128 	 * configuration, destroy structures.
    129 	 */
    130 #ifdef _MODULE
    131 	devsw_detach(NULL, &npf_cdevsw);
    132 #endif
    133 	npf_unregister_pfil();
    134 	npf_core_destroy(npf_core);
    135 	npflogdetach();
    136 
    137 	/* Note: order is particular. */
    138 	npf_nat_sysfini();
    139 	npf_alg_sysfini();
    140 	npf_session_sysfini();
    141 	npf_tableset_sysfini();
    142 	percpu_free(npf_stats_percpu, NPF_STATS_SIZE);
    143 	rw_destroy(&npf_lock);
    144 
    145 	return 0;
    146 }
    147 
    148 /*
    149  * Module interface.
    150  */
    151 static int
    152 npf_modcmd(modcmd_t cmd, void *arg)
    153 {
    154 
    155 	switch (cmd) {
    156 	case MODULE_CMD_INIT:
    157 		return npf_init();
    158 	case MODULE_CMD_FINI:
    159 		return npf_fini();
    160 	default:
    161 		return ENOTTY;
    162 	}
    163 	return 0;
    164 }
    165 
    166 void
    167 npfattach(int nunits)
    168 {
    169 
    170 	/* Void. */
    171 }
    172 
    173 static int
    174 npf_dev_open(dev_t dev, int flag, int mode, lwp_t *l)
    175 {
    176 
    177 	/* Available only for super-user. */
    178 	if (kauth_authorize_generic(l->l_cred, KAUTH_GENERIC_ISSUSER, NULL)) {
    179 		return EPERM;
    180 	}
    181 	return 0;
    182 }
    183 
    184 static int
    185 npf_dev_close(dev_t dev, int flag, int mode, lwp_t *l)
    186 {
    187 
    188 	return 0;
    189 }
    190 
    191 static int
    192 npf_dev_ioctl(dev_t dev, u_long cmd, void *data, int flag, lwp_t *l)
    193 {
    194 	int error;
    195 
    196 	/* Available only for super-user. */
    197 	if (kauth_authorize_generic(l->l_cred, KAUTH_GENERIC_ISSUSER, NULL)) {
    198 		return EPERM;
    199 	}
    200 
    201 	switch (cmd) {
    202 	case IOC_NPF_VERSION:
    203 		*(int *)data = NPF_VERSION;
    204 		error = 0;
    205 		break;
    206 	case IOC_NPF_SWITCH:
    207 		error = npfctl_switch(data);
    208 		break;
    209 	case IOC_NPF_RELOAD:
    210 		error = npfctl_reload(cmd, data);
    211 		break;
    212 	case IOC_NPF_TABLE:
    213 		error = npfctl_table(data);
    214 		break;
    215 	case IOC_NPF_STATS:
    216 		error = npfctl_stats(data);
    217 		break;
    218 	case IOC_NPF_SESSIONS_SAVE:
    219 		error = npfctl_sessions_save(cmd, data);
    220 		break;
    221 	case IOC_NPF_SESSIONS_LOAD:
    222 		error = npfctl_sessions_load(cmd, data);
    223 		break;
    224 	default:
    225 		error = ENOTTY;
    226 		break;
    227 	}
    228 	return error;
    229 }
    230 
    231 static int
    232 npf_dev_poll(dev_t dev, int events, lwp_t *l)
    233 {
    234 
    235 	return ENOTSUP;
    236 }
    237 
    238 static int
    239 npf_dev_read(dev_t dev, struct uio *uio, int flag)
    240 {
    241 
    242 	return ENOTSUP;
    243 }
    244 
    245 /*
    246  * NPF core loading/reloading/unloading mechanism.
    247  */
    248 
    249 static void
    250 npf_core_destroy(npf_core_t *nc)
    251 {
    252 
    253 	npf_tableset_destroy(nc->n_tables);
    254 	npf_ruleset_destroy(nc->n_rules);
    255 	npf_ruleset_destroy(nc->n_nat_rules);
    256 	kmem_free(nc, sizeof(npf_core_t));
    257 }
    258 
    259 /*
    260  * npf_reload: atomically load new ruleset, tableset and NAT policies.
    261  * Then destroy old (unloaded) structures.
    262  */
    263 void
    264 npf_reload(npf_ruleset_t *rset, npf_tableset_t *tset, npf_ruleset_t *nset)
    265 {
    266 	npf_core_t *nc, *onc;
    267 
    268 	/* Setup a new core structure. */
    269 	nc = kmem_alloc(sizeof(npf_core_t), KM_SLEEP);
    270 	nc->n_rules = rset;
    271 	nc->n_tables = tset;
    272 	nc->n_nat_rules = nset;
    273 
    274 	/* Lock and load the core structure. */
    275 	rw_enter(&npf_lock, RW_WRITER);
    276 	onc = atomic_swap_ptr(&npf_core, nc);
    277 	if (onc) {
    278 		/* Reload only necessary NAT policies. */
    279 		npf_ruleset_natreload(nset, onc->n_nat_rules);
    280 	}
    281 	/* Unlock.  Everything goes "live" now. */
    282 	rw_exit(&npf_lock);
    283 
    284 	/* Turn on/off session tracking accordingly. */
    285 	npf_session_tracking(true);
    286 
    287 	if (onc) {
    288 		/* Destroy unloaded structures. */
    289 		npf_core_destroy(onc);
    290 	}
    291 }
    292 
    293 void
    294 npf_core_enter(void)
    295 {
    296 	rw_enter(&npf_lock, RW_READER);
    297 }
    298 
    299 npf_ruleset_t *
    300 npf_core_ruleset(void)
    301 {
    302 	KASSERT(rw_lock_held(&npf_lock));
    303 	return npf_core->n_rules;
    304 }
    305 
    306 npf_ruleset_t *
    307 npf_core_natset(void)
    308 {
    309 	KASSERT(rw_lock_held(&npf_lock));
    310 	return npf_core->n_nat_rules;
    311 }
    312 
    313 npf_tableset_t *
    314 npf_core_tableset(void)
    315 {
    316 	KASSERT(rw_lock_held(&npf_lock));
    317 	return npf_core->n_tables;
    318 }
    319 
    320 void
    321 npf_core_exit(void)
    322 {
    323 	rw_exit(&npf_lock);
    324 }
    325 
    326 bool
    327 npf_core_locked(void)
    328 {
    329 	return rw_lock_held(&npf_lock);
    330 }
    331 
    332 /*
    333  * NPF statistics interface.
    334  */
    335 
    336 void
    337 npf_stats_inc(npf_stats_t st)
    338 {
    339 	uint64_t *stats = percpu_getref(npf_stats_percpu);
    340 	stats[st]++;
    341 	percpu_putref(npf_stats_percpu);
    342 }
    343 
    344 void
    345 npf_stats_dec(npf_stats_t st)
    346 {
    347 	uint64_t *stats = percpu_getref(npf_stats_percpu);
    348 	stats[st]--;
    349 	percpu_putref(npf_stats_percpu);
    350 }
    351 
    352 static void
    353 npf_stats_collect(void *mem, void *arg, struct cpu_info *ci)
    354 {
    355 	uint64_t *percpu_stats = mem, *full_stats = arg;
    356 	int i;
    357 
    358 	for (i = 0; i < NPF_STATS_COUNT; i++) {
    359 		full_stats[i] += percpu_stats[i];
    360 	}
    361 }
    362 
    363 /*
    364  * npfctl_stats: export collected statistics.
    365  */
    366 static int
    367 npfctl_stats(void *data)
    368 {
    369 	uint64_t *fullst, *uptr = *(uint64_t **)data;
    370 	int error;
    371 
    372 	fullst = kmem_zalloc(NPF_STATS_SIZE, KM_SLEEP);
    373 	percpu_foreach(npf_stats_percpu, npf_stats_collect, fullst);
    374 	error = copyout(fullst, uptr, NPF_STATS_SIZE);
    375 	kmem_free(fullst, NPF_STATS_SIZE);
    376 	return error;
    377 }
    378